math.erf unavilable

[chaseaucoin]

Hi there,

For some of the stuff I'm doing it would be nice to have access to math.erf

https://www.tensorflow.org/api_docs/python/tf/math/erf

I tried using the patterns I saw in this library to do the following

` static Tensor erf(Tensor x, string name = null)
{
var results = tf.Runner.TFE_FastPathExecute(tf.Context, tf.Context.DeviceName,
"Erf", name,
null,
x);

        return results[0];
    }`

This seemed to be the right key given:
https://github.com/tensorflow/tensorflow/blob/e433b66b7a82920e072eb7526560e2b07411633a/tensorflow/core/kernels/cwise_op_erf.cc

That gave me the error: 'The given key 'Erf' was not present in the dictionary.'

I'm using Tensorflow.NET 0.32.0.0 with SciSharp.TensorFlow.Redist-Windows-GPU 2.4.0

Any help would be appreciated.

[Oceania2018]

@chaseaucoin Added tf.math.erf as c8643c4, if you found more missing functions, you can follow the pattern to add, welcome to PR.